Brown the butter by melting in a medium saucepan over medium heat. Stir occasionally. When the butter begins to foam, stir constantly until it turns a deep golden brown. Watch carefully because at this point the color changes quickly. It takes about 7 minutes to brown the butter.

Cool to room temperature, about 1 hour.

Preheat the oven to 350 degrees. Mix the flour and baking powder together. Add the cooled butter and vanilla to the sugar in a medium bowl and stir until evenly mixed. Add the flour and mix to form a dough.

Shape the dough into balls using rounded teaspoons of dough. Place on baking sheets and press a crisscross pattern with the fork. Dip the tines of the fork in a little flour if the dough sticks.

Bake 10 to 12 minutes. The cookies do not brown much, so touch them lightly to see if they are set. Cool the cookies on the baking sheet for 2 minutes before removing to a wire cooling rack. The cookies are fragile until they cool.